Resistance device



, L. KEBLER.

RESISTANCE DEVICE.

APPLICATION FILED OCT. 23. 1915.

,347,102. Patented July 20, 192(] 10 11 /0 11 11 5 r g 73 26 44 9 9 I 11 16 2 0 10 l l I I: 7 4 7 f 2 Ill ml n.

1 LL 21 I 3% 114?.) fi'lttozmaw UN-rr'ED STATES" PATENT. OFFICE.

Lnommn x-nBLEra or naonxvrnnirnnw YORK, assrenon 'ro' wean LEONARD nnnc'rnrc 00., A conronnrron or NEW roan.

" Bronxville, in the county of Westchester and State ofNew York, have invented certain new and useful Improvements in Resistance Devices, of which the following is a full, clear, and exact specification. H

My invention relates to improvements in resistance devices or rheostats and method of makin same, andparticularly to that type in which the resistive conductor is embedded or covered by an insulating coating, such as enamel, cement and the like.

n this type of resistance device, there is an insulating base on which theresistive conductor is supported or attached'and an adhesive insulating .coating is afterward spread over the conductor and supportjand baked or otherwise caused to solidify so as to firmly hold the; conductor in place and protect-the conductor from deterioration and from \mechanieal injury .or displace-' ment. In such devices it is necessary to accurately space-and position the conductor and terminals to which the conductor may be connected before the first insulating coating is applied. As compactness is desirable, re-

quiring the parts of the resistive conductor to be spaced from adjoining parts by a com; paratively short distance, and also to be r uniformly spacedi it has previously required considerab e time -'and exp'ense to properly position the conductor-. s'md terminals, and to retain the same in position during the application of the insulating coating. The main object of myinvention is to provide a construction wh1ch'wi1l-facilitate the application of the resistive con-' ductor to the base in its proper position as well as the terminals and also retain these parts in their-proper position during the application of the insulating coating, also pro-- vide a form" of construction and; means which economizes space in positioning the parts, secure a high degree of insulation be-- tween-the parts and reduce the expense of manufacture. Other objects {and advantages of my ihventioniwill be understood from the following desc iption and accompanying drawings. f

Figural 1s aplan vew'of" one form 'of invention with certain parts removed; Fig.

Specification of Letters Patent.

Application filed October 23, 1915: Serial No. 57,402.

Patented Jul 20,1920.

2 is a plan view of the device complete, and Fig. 3 is a vertical cross section of the base portion on the line 3-3 of Fig. 1.

'In the particular embodiment of my invention illustrated in' the drawings, there is v a base 4;"of' circular form havingsuitable supports or extensions 5 for securing the same in position as may be desired, such as to the base of a fan motor. The base may be of porcelainor other suitable insulating mater1al, 01"111 somecases may be in the form of an insulating coating or ground coat applied to a main support of other materlal. The lnsulating base or coating has a series of projections 6 extending from the surface ofthebase and is also shown as having extending from such projections the strips 7 which are shown as substantially parallel to each other forming aseries of channels between them. The projections 6 and strips 7 are shown as being of the same bedded in-the insulating base .or may other-'- wise be supported therefrom. The channels formed by the stri s and "pro'ections communicate with a joining around the projections 6. At 8are shown a number of projections fromr the base of H form, these projections also beingindicated as integral with and of the same material as the base and preferably molded therewith.

Over the central'cross portion of these projections are located the terminals of the 8 5 c annels rheostat. These are in.- theform ofmetal strips bent around the central pfi't'of the projections 8, each tei'minal having horizontal end portions 10, which are located againstthe main surface of the base 4, vertical portions lI extending a wardly along the sides of the central part o the H formed projections, and top portions marked'9 over the central portion of the H formed pro'jec-' tions. The terminals are thus bent or ;.-'10oped over the, central part of the projectiohs 8,:these projections thus holding ilthe terminals in adefinit'e position. rheostat or resistance device embodying my The resistive conductor 12"is shown of zigzag or wave form, one end being electrically connected to the terminal portion 13, the end of the terminal being bent over so as to pinch and firmly secure the efiEFof the resistive conductor. ductor is shown as extending from the terminal portion 18 through the right hand channel around the lower right hand projection 6, down-the next channel and so on, until it finally reaches and is electrically connected to the terminal portion 14 by being pinched under the end of theterminal. The middle terminal is electrically connected to an intermediate portion of the revsistive conductor as shown at 15 by a portion of the ,terminal being bent over tov clamp the resistive conductor. The lead wire 16 extends from the terminal portion 13 to the terminal 17, the latter being a screw and nut terminal located at and secured to the side of the base for connection to the external circuit. 'At one part of the the parts'in place. A wire 25, having its ends bent into and passing through the holes 26 formed in the base, serves as a guard and for holding the lever 23 against the terminals} Around the outer edge, of

thebase are raised portions 27 which with other raised parts form a continuous outer inclosing edge.

The base having been molded in the. form and with the projecting portions as above described, the device is assembled by. first securing an end of the resistive conductor to an end portion 13 of one of the termin ls fee andthe lead 16 connected thereto, and he terminal being bent .in proper sha e is slipped over the central portion 0 the right-hand projection 8.' The resistive conductor is then fed down through the .righthand channel and bent around the lower right-hand projection 6 and then passed upthe next channel and bent around the next projection 6, and so on until at the point where the next terminal is to be connected. The end of the terminal is bent over the resistive conductor so as to firmly clamp it and this terminal is then placed in osition-upon its projection 8. The resistlve conductor is then passed along the succeeding channels and around projections 6 until the end of the resistive conductor is reached, which end is then fastened to the remaining terminal, and the terminal placed in its proper position. In some cases the terminals are first secured to the The resistive con-,

resistive conductor at their proper points before starting to apply the parts to the base. With the parts placed in position as described, the heads 6 of the strips serve to definitely positibn and hold the conductor where the conductor is looped, and the strips 7 serve to "prevent the conductor from bending and-from moving sidewise out of its proper position. The terminals also are properly positioned by the projections. 8 with the end portions of the terminals lying flatwise against the base. The insulating coating 28 is next applied over the resistive conductor and over the flat portions of the terminals which lie against the base, openings between the projections permitting the insulating coating to be a plied or flowed evenly .over the parts. he resistance device is-th'en baked or otherwise treated so as to solidify the insulating coating which will adhere to the base and hold all parts in a permanently fixed position. In some cases it may be desirable, to apply more than one coating, but'by means of my invention 1 am enabled to secure excellent results by the application of one coating only, because the channels and projecting portions serve to so definitely locate all parts and provide such excellent guides and supports for the insulating coating that the one coating mabe evenly and conveniently ap lied over a 1 parts. he coating will pre erably cover the projecting parts 6 and strips 7 so that the v exposed surface of the insulating coating w1ll present a comparatively smooth and finished appearance.

After the insulating coating has been baked or caused'to set, the lead 16 is secured to the terminal 17, and the lever 23, plate 21 and terminal 22 placed in position, and the uide rod or wire 25 is secured in place.

he lever is shown in the off position in Fig. 2; by movement to the right all of the resistance will be included in circuit between the two'terminals 17 and 22 by reason of the lever engaging with the lefthand contact surface 9. Further movement to the right will causethe lever to engage the middle contact surface 9, and cut out a portion of the resistance from circuit and further movement to the right-handposition will cause all of the resistance to be cut out of circuitby the contact lever engaging the right-hand contact surface ,9.

It is apparent that by-means of my inven' tion the resistance device or rheostat is very quickly and conveniently manufactured, and that "the cost of manufacture is The construction also secures compactness, is very durable, and is substantially free from chance of mechanical injuiy.

n some instances, the base may have the channels only slightly larger than the size conductor before the application of the insulating coating. It is apparent ,that my invention may be embodied in various forms of construction other than that herein par} ticularly shown and described.

Having thus described my invention, what I declare as-new and desire to secure by Letters Patent of the United States is 1. In a resistance device, an insulating base plate, a resistive conductor on and contacting with said plate, contact terminals on said plate, said plate having projecting portions for positioning said conductor and said terminals, and an insulating coating embedding said conductor and overlying portions of said'contact terminals.

2. In a resistance device, an insulating base, said base having a plurality of ribs and widened heads at the ends of the ribs,

, 'a resistive conductor located on said base between said ribs and passed around and positioned by said heads, and an adhesive insulating coating embedding said conduc tor.

3. In a'resistance device, an insulating base, said base having insulating projecting portions extendingtherefrom, contact terminals positioned by said projecting portions, said terminals having extensions engaging the surface ofsaid base, a resistive conductor connected with said terminals,

and an adhesive insulating coating embedding the portions of said terminals which engage the surface of said base.

4. In a resistance device, an insulating base, said base having projecting portions, contact terminals of U-shape having end portions engaging the surface of said base, said terminals engaging and positioned by said projections, a resistive conductor, and an insulating adhesive coatinge-mbedding the portions of said terminals engaging the surface of the base and also embedding said conductor.

. 5. The method of making a resistance device which consists in provlding a base portion of insulating material with insulating projections therefrom, placing a resistive conductor in contact with said base portion and between certain of said projections, placing terminals over certain of said projections, and embedding said conductor and portions of said terminals with an insulating adhesive coating.

6. An electrical resistance device comprising a base plate of insulating material having parallel projecting ridges on its un-.

der surface forming channels, said ridges having widened heads at "alternate ends thereof, a resistive conductor within said channels and in contact with the surface of said plate and alternately inicontact with the sides of said ridges and extendin around said widened heads, and an adhering coating of insulating material covering said conductor and binding all the parts into a solid unitary mass.

In testimony whereof I afiix my signature in presence of two witnesses.

- LEONARD KE-BLER. Witnesses:

JOHN Q. GAUBERT, D. J. BURNS.

channels and in' contact with the surface of 

